Engine



C. H. FROST.

ENGINE.

APPLICATION FILED MAY 6, 1920.

Patentedi Apr.- 26; 1921 3 SHEETS SHEET 1.

attorney C. H. FROST.

ENGINE.

APPLICATION FILED'MAY 6, 1920.

1,376,267. Patented Apr. 26, 1921.

3 SHEETSSHEET 2.

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wuewtoz v C. H. FROST.

ENGINE.

APPLICATION FILED MM 6', 1920.

Patented Apr. 26, 1921.

3 SHEET SSHEET 3.

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UNITED STATES PATENT OFFICE.

CLAYTON H; FROST, F ORANGE, NEW JERSEY.

ENGINE.

Specification of Letters Patent.

Patented Apr. 26, 1921.

Application filed May 6, 1920. Serial No. 379,227.

. which the following is a specificatio This invention relates to engines, and it comprises an engine havlng a cylinder, a

pair of reciprocating pistons arranged'in the cylinder, one of said pistons being arranged within the other, the throw of the pistons being of different lengths, whereby the pistons move toward and away from each other, a fuel inlet, means for admitting air into the space between the pistons whereby said air is compressed when the pistons approach each other, means for delivering the air into the cylinder, and means for exhausting burned gases from the cylinder; all as more fully hereinafter set forth and as claimed.

In the present invention, I have produced an oil engine in which the possibility of premature explosions is eliminated and in which the explosion occurs at the instant of maximum pressure. The engine fires on every stroke of the piston and also exhausts on every stroke of the piston. The inlet and exhaust are so arranged that the old charge, or burned gases, is entirely removed from the cylinders before the new charge is admitted.

The compression, explosion, and exhaust occur separately in their proper order in the manner of the ordinary four-cycle en gine, but there is an explosion for every downward stroke of the piston as in the two-cycle engine.

The engine may also be utilized as a gas engine by placing the carbureter in the feed pipe to the. air inlet and arranging the usual ignition or sparking devices in the cylinder. I

In the accompanying drawings, I have.

shown an advantageous embodiment of the invention. In this showing,

Figure 1 is a vertical sectional view of one of the cylinders.

Fig. 2 is a similar view at right angles to Fig. 1. p Fig. 3 is a view similar to Fig. 1 showing the exhaust, and

Fig. 4 is a similar view showing each of the p1s tons at the lowermost position at the beglnnlng of the inlet stroke.

Referring to the drawings, the engine comprises a cylinder 1 provided with the usual cylinder head 2, the cylinder and head having a water-jacket 3 of ordinary construction. Below the cylinder, there is arranged a crank case 4 and main crank shaft.

5 1s mounted in bearings 6 at each side of the crank case.

A pair of pistons 7 and 8 are arranged in each cylinder, the inner piston 8 being arranged to travel within the outer piston 7 The two pistons are provided with cranks ofdifi'erent lengths whereby the inner piston travels a greater distance than. the outer piston during each stroke (see Fig. 2). The

outer piston is connected to the shaft by cranks 9 and connecting rods 10. Cranks 11 are arranged on the eccentric portions 12 earned by the cranks 9 and the connecting rods 13 of the inner pistons are secured to these cranks. By referring to Fig. 2, it will be seen that the cranks 11 are arranged at a greater distance from the center of the main crank shaft 5 whereby the length of the stroke of the inner piston is much greater than the stroke of the outer piston.

The cylinder is provided with a fuel inlet 14 communicating'with the fuel passage 15. A second passage 16 is connected to the passage 15 and enters the cylinder at a point farther removed from the cylinder head. The outer piston is provided with a port 17 adapted to register with the passage 16 at the end of the intake stroke. An air inlet 18 is arranged in the cylinder near the opposite end. The inner piston is provided with a passage 19 extending from the head of the piston to one side.

Exhaust outlet 20 in the cylinder communicates with a assage 21 in the cylinder wall which exten s toa chamber 22 in the side wall of the cylinder. The outer piston is provided with passages 23 and 24; and the inner piston is provided with aflport 25 which is adapted to register at a given time to permit communication between the exhaust chamber 22 and the exhaust outlet 26 (see Fig. 3).=

The operation of the engine is as follows: Starting onthe cycle ofevents with the pistons in the position shown in Fig. 1, the

head, has been closed by the downward movement of the outer piston, port 17 having' been moved out of communication therewith. "During the downward stroke, open ing 18 in the wall of the outer piston communicates with the air inlet 18 and permits air to enter the space between the two pis- .tons, the inner piston having previously movedqto a point beyond this opening (see Fig. 4). The admissionuof air continues until the end of the downward stroke of the two pistons. The outer piston completes its downward stroke before the inner piston, whereby the space between the two pistons continues to enlarge for a brief interval allowing continued admission of air.

During the upward stroke of the two pis tons, the ports '23 and 24 in the outer piston and the passage 25 in the inner piston establish communication between the exhaust chamber 22 and the exhaust outlet 26, permitting the exhaust from, the previous explosion to discharge from the exhaust chamber. -This operatlon takes place just before the end of the upward stroke (see Fig. 3).

During the upward stroke of the pistons, the air inlet opening is closed by the inner piston and'the charge of air contained in the space between the two pistons is comressed as the size of the space is diminis'hed. The air is compressed to its maximum, or to the desired point, just at the conclusion of the upward stroke of the outer piston, and at this instant, communication is established between the passage 19 inthe inner piston, the port 17 in the outer piston, and the passage 16 in'the cylinder wall, the

compressed air being discharged into, the

inlet port 15 and thence to the explosion chamber in the cylinder head. A charge of atomized fuel is delivered to the explosion chamber through the inlet 14 at the proper instant to mix with the highly compressed air and form an explosive mixture. It will be apparent that premature explosions are entirely eliminated as there can be no high compression in the explosion chamber until the ports 15, 16, 17, and 19 have come in communication with. each other to permit passage of the compressed air to the explosion chamber, and this does not occur until after the outer piston has started on its downward stroke. At the instant of maximum pressure, the outer piston closes the passage 16 and the explosion occurs.

The exhaust. gases are discharged from during the upward'stroke of the pistons at the same time the air is being compressed and are entirely removed from the cylinder before the new charge is admitted. On the next cycleof the engine, the exhaust gases in the chamber 22 are delivered to the exhaust outlet in a manner heretofore explained.

From the above description, it is believed that the operation of the invention will be apparent to those skilled in the art. It will be seen that I have produced-a two-cycle engine in which the possibilities of premature explosions are removed; in which the mixture of the fresh charge and exhaust gases isrendered impossible and inwhich the new charge is highly compressed before the explosions; p

The engine may be operated as a gasolene engine by closing port 14, arranging sparking devices in the cylinder head and connecting the gas feed to the inlet 18.

Although I have shown and described a preferred embodiment of the invention, .it

1. An engine comprising a cylinder, a

pair of pistons having throws of different from the spirit of theinvention or the scope engths arranged therein, one of said pistons being disposed within the other, the cylinder being provided with an inlet, means for establishing communication between said inlet and the s ace between said pistons, means for establis ing communication between said space and the interior of said cylinder, the interior of said cylinder being provided with an exhaust opening, the cylinder wall being provided with a passage communicating with said opening, an exhaust chamber arranged on one side of said cylinder, said passage communicating with said exhaust chamber, and an exhaust outlet communicating with said exhaust chamber, the communication being controlled by the travel of the pistons.

2. An engine comprising a cylinder, a pair of pistons having throws of different lengths arranged in said cylinder, one of said pistons being disposed within the other, the cylinder being provided with an inlet, means for establishing communication between said inlet and the space between said pistons, means for establishing communication between said space and the interior of said cylinder, an exhaust chamber, means for establishing communication between said exhaust chamber and the cylinder, an

exhaust outlet communicating with said ex-' travel of said pistons to control the communication between said exhaust chamber and said exhaust outlet.

3. An engine comprising a cylinder, a pair of pistons having throws of different lengths arranged therein, one of said pistons being disposed within the other, the cylinder being provided with an inlet,

mneans for establishing communication between said inlet" and the space between said pistons, means for establishing communication between said space and the interior of the cylinder, an exhaust chamber, means for establishing communication between said exhaust chamber and the cylinder, thev pistons being provided with passages adapted to register with each'other and with the exhaust chamber at apredetermined point in the cycle, and an exhaust outlet registering with said passages to permit exhaust from said chamber.

In testimony whereof I afiix my signature in presence of two witnesses.

CLAYTON HQFROST.

Witnesses: H

ALBnR'n H. WILLIAMS, DONALD Fla-WILLIAMS. 

